unix: add NLMSGERR constants for netlink extended acknowledgement

Change-Id: I8d23fc227d1f61b823abcf610479005356c52088
Reviewed-on: https://go-review.googlesource.com/c/sys/+/286072
Trust: Matt Layher <mdlayher@gmail.com>
Run-TryBot: Matt Layher <mdlayher@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
diff --git a/unix/linux/types.go b/unix/linux/types.go
index 321cb8f..7efe890 100644
--- a/unix/linux/types.go
+++ b/unix/linux/types.go
@@ -3655,3 +3655,11 @@
 	CLOSE_RANGE_UNSHARE = C.CLOSE_RANGE_UNSHARE
 	CLOSE_RANGE_CLOEXEC = C.CLOSE_RANGE_CLOEXEC
 )
+
+// Netlink extended acknowledgement TLVs.
+
+const (
+	NLMSGERR_ATTR_MSG    = C.NLMSGERR_ATTR_MSG
+	NLMSGERR_ATTR_OFFS   = C.NLMSGERR_ATTR_OFFS
+	NLMSGERR_ATTR_COOKIE = C.NLMSGERR_ATTR_COOKIE
+)
diff --git a/unix/ztypes_linux.go b/unix/ztypes_linux.go
index 33ca503..c769e73 100644
--- a/unix/ztypes_linux.go
+++ b/unix/ztypes_linux.go
@@ -3714,3 +3714,9 @@
 	CLOSE_RANGE_UNSHARE = 0x2
 	CLOSE_RANGE_CLOEXEC = 0x4
 )
+
+const (
+	NLMSGERR_ATTR_MSG    = 0x1
+	NLMSGERR_ATTR_OFFS   = 0x2
+	NLMSGERR_ATTR_COOKIE = 0x3
+)